Motorized Extension Ladder

Abstract

A motorized extension ladder comprising a stationary first section, a moveable second section which is reversibly moveable from a proximate location to a distal location, a first cable pulley system with a first cable and first pulley to reversably move said moveable section from said proximate location to said distal location, and back, by a motor. The motor can be permanently affixed to the ladder, or operatively connected as required. A series of pulleys is provided which are moveable by rotation of a threaded rod, in order to cause the moveable section of the ladder to extend or retract. A motorized method for extending or retracting an extension ladder is provided.

What is claimed is: 
     
         1 . A motorized extension ladder comprising a stationary first section, a moveable second section which is reversibly moveable from a proximate location to a distal location, a first cable pulley system with a first cable and first pulley to reversably move said moveable section from said proximate location to said distal location, and back, and which extension ladder is characterized by a motor, which is attached to, or which can be operatively attached to, said first cable of said first pulley system. 
     
     
         2 . A motorized extension ladder as claimed in  claim 1  wherein said motor is connected to a second pulley system which comprises at least one pulley attached to a fixed pulley support, at least one pulley attached to a moveable pulley support, and a second cable operatively wound around said pulleys, and operatively connected to said first cable pulley system, and wherein said motor moves said movable pulley support, with respect to fixed pulley support. 
     
     
         3 . A motorized extension ladder as claimed in  claim 1  wherein said motor is an electric or pneumatic motor which is operatively connected to, or connectable to, a rotatable threaded rod which rod is fixed at one end to said fixed pulley support, and connected to a threaded nut on said moveable pulley support, so that rotation of said threaded rod causes said moveable pulley support to move along said threaded rod, and thus pull or release said second cable. 
     
     
         4 . A motorized extension ladder as claimed in  claim 2  wherein said first cable and the second cable, are typically the same cable. 
     
     
         5 . A motorized extension ladder as claimed in  claim 1  wherein said first and second cable are ropes, wires, chains, strings, or straps. 
     
     
         6 . A motorized extension ladder as claimed in  claim 1  wherein said second pulley system is located within a housing affixed to the ladder. 
     
     
         7 . A motorized extension ladder as claimed in  claim 6  wherein said housing is located on a side of the ladder, or is placed underneath a rung of the ladder. 
     
     
         8 . A motorized extension ladder as claimed in  claim 1  wherein said ladder also comprises a locking device which locks the moveable section in position between said proximate and distal location. 
     
     
         9 . A motorized extension ladder as claimed in  claim 1  wherein said motor is a battery driven DC motor. 
     
     
         10 . A motorized extension ladder as claimed in  claim 1  wherein said battery driven DC motor is connected to a battery pack, and wherein said battery pack is removeable for recharging. 
     
     
         11 . A motorized extension ladder as claimed in  claim 2  wherein said second cable passes around a first pulley located on the fixed pulley support, and then passes to the pulley located on said moveable pulley support. 
     
     
         12 . A motorized extension ladder as claimed in  claim 11  wherein said cable additionally passes back and forth between additional pulleys located on both the fixed and moveable pulley support structures. 
     
     
         13 . A motorized extension ladder as claimed in  claim 12  wherein a second series of pulleys is added. 
     
     
         14 . A motorized extension ladder as claimed in  claim 11  wherein, for each cable, each of the fixed and moveable pulley support structures will include between 2 and 6 pulleys each. 
     
     
         15 . A motorized extension ladder as claimed in  claim 14  wherein each of the fixed and moveable pulley supports will include between 3 and 5 pulleys each. 
     
     
         16 . A motorized extension ladder as claimed in  claim 1  wherein said threaded rod has a length of between 25 and 150 cm in length 
     
     
         17 . A motorized extension ladder comprising a stationary first section, a moveable second section which is reversibly moveable from a proximate location to a distal location, a first cable pulley system with a first cable and first pulley to reversably move said moveable section from said proximate location to said distal location, and back, and which extension ladder is characterized by a motor, which is attached to said first cable of said first pulley system, and wherein said motor is connected to a second pulley system which comprises at least one pulley attached to a fixed pulley support, at least one pulley attached to a moveable pulley support, and a second cable operatively wound around said pulleys, and operatively connected to said first cable pulley system, and wherein said motor moves said movable pulley support, with respect to fixed pulley support, and wherein said motor is an electric or pneumatic motor which is operatively connected to a rotatable threaded rod which rod is fixed at one end to said fixed pulley support, and connected to a threaded nut on said moveable pulley support, so that rotation of said threaded rod causes said moveable pulley support to move along said threaded rod. 
     
     
         18 . A motorized extension ladder as claimed in  claim 16  wherein said motor is a 12 to 24 volt, variable speed, reversible drill motor. 
     
     
         19 . A motorized extension ladder comprising a stationary first section, a moveable second section which is reversibly moveable from a proximate location to a distal location, a first cable pulley system with a first cable and first pulley to reversably move said moveable section from said proximate location to said distal location, and back, and which extension ladder is characterized by a spindle to which a motor can be connected, wherein said spindle is attached to said first cable of said first pulley system, and wherein said spindle is connected to a second pulley system which comprises at least one pulley attached to a fixed pulley support, at least one pulley attached to a moveable pulley support, and a second cable operatively wound around said pulleys, and operatively connected to said first cable pulley system, and wherein said spindle, when connected to said motor, moves said movable pulley support, with respect to fixed pulley support, and wherein said spindle is operatively connected to a rotatable threaded rod which rod is fixed at one end to said fixed pulley support, and connected to a threaded nut on said moveable pulley support, so that rotation of said threaded rod causes said moveable pulley support to move along said threaded rod. 
     
     
         20 . A motorized extension ladder as claimed in  claim 19  wherein said motor is a 12 to 24 volt, variable speed, reversible drill.